WEED MIGRATION 



727 



Fig. 550. Curled Dock (Bumex crispus). A common European weed now 



occurring across the continent. 



(After Chesnut, U. S. Dept. Agr.) 



found in the northwest. A few of the abundant species may be 

 mentioned. Russian thistle {Salsola kali var. tenuifolia) is abun- 

 dant in the drier regioiis, especially east of the Cascades. In the 

 Puget Sound country are found such common European weeds as 

 Canada thistle {Cirsium arvense), bull thistle (C. lanceolatum) , 

 batehelor's button {Centaurea cyanus), chicory {Cichorium iniy- 

 bus), common mustard {Brassica arvensis), mullein (Verbascum 

 thapsus) and also V. blattaria, and toadflax (Linaria vulgaris)'. 

 It is not uncommon to find in clearings of the forest the small 

 Kenilworth ivy (Linaria cymbalaria) , the common pansy {Viola 

 tricolor), the petunia {Petunia grandiflora) , the dead nettles {La- 

 mium amptexicaule and L. album), ox-eye daisy {Chrysanthemum 

 leucanthemum) , hemp nettle {Galeqpsis tetrahit), foxglove {Digi- 

 talis purpurea) , European bindweed {Convolvulus arvensis). The 



